DE102018109306A1 - Method for producing an electrical heating device - Google Patents

Abstract

Provided is a method of making an electric heater (100,200,300,400,500,600,700) comprising the steps of providing a sleeve (130,230,330,430,530, 630,730) of a first material having a first strength, disposing an electrical heating element (110,210,310,410, 510,610,710) in the sleeve (130,230,330,430,530, 630,730 Placing a filler material (120,220, 320,420,520,620,720) in the sleeve (130,230,330,430,530,630,730) so that current carrying parts of the electrical heating element (110,210,310,410, 510,610,710) are electrically insulated from the sleeve (130,230,330,430,530,630,730) and the location of the electrical heating element (110,210,310, 410,510,610,710) in the sleeve (130,230, 330,430,530,630,730) is fixed, and at least partially compressing the sleeve (130,230,330,430,530,630,730) of the electrical heating element (110, 210, 310, 410, 51) arranged in sections of the sleeve (130,230,330,430, 530,630, 730) which are compressed 0,610,710) and the filling material (110,210,310,410,510,610,710) to be compacted in portions of the sleeve (130,230,330,430,530,630,730), wherein a tube portion (140,240,340,440, 540,640,740) is placed before completion of at least partially compacting the sleeve (130,230,330,430,530,630,730) at portions to be compacted of a second material having a second strength higher than the first strength.

Description

Electric heaters, which have a sleeve with an electrical heating element disposed therein, the current-carrying parts of which are electrically insulated from the sleeve, are a standard means for the electrical heating of objects and / or media.

For many concrete embodiments of such electrical heating devices there is a desire on the one hand for the highest possible compression in order to ensure the best possible heat conduction from the electric heating element to the sleeve, which is brought into contact with the object or medium, while at least locally applicable Compression must be limited, for example because in the sleeve at some points further, pressure-sensitive elements, eg Electronic components are arranged or because there is undesirable caused by excessive compression deformation. This is taken into account by compressing the sleeve to different degrees in different sections.

However, the realization of this approach in the manufacturing process has so far proven to be less reliable. In other electric heating cartridges manufacturing problems result from the fact that the strength of the sheath material is not sufficient, for example, if a sleeve made of ultrapure titanium is required for medical applications.

The object of the invention is therefore to provide a process, which is improved in particular with regard to its process reliability, for producing an electrical heating device, in particular a heating cartridge or a tubular heating element.

This object is achieved by a method having the features of claim 1. Advantageous developments of the method are the subject of the dependent claims.

• - Bereitstellen einer Hülse aus einem ersten Material, das eine erste Festigkeit aufweist,
• - Anordnen eines elektrischen Heizelements in der Hülse,
• - Anordnen eines Füllmaterials in die Hülse, so dass stromdurchflossene Teile des elektrischen Heizelements von der Hülse elektrisch isoliert sind und die Lage des elektrischen Heizelements in der Hülse fixiert ist, und
• - zumindest abschnittsweises Verdichten der Hülse, des in Abschnitten der Hülse, die verdichtet werden, angeordneten elektrischen Heizelements und des in Abschnitten der Hülse, die verdichtet werden angeordneten Füllmaterials

auf. Erfindungswesentlich ist, dass vor dem Abschluss des zumindest abschnittsweisen Verdichtens der Hülse bei zu verdichtenden Abschnitten ein Rohrabschnitt angeordnet wird, der aus einem zweiten Material, das eine zweiten Festigkeit aufweist, die höher ist als die erste Festigkeit, besteht.The method according to the invention for producing an electrical heating device comprises the steps

• Providing a sleeve of a first material having a first strength,
• Arranging an electric heating element in the sleeve,
• Placing a filling material in the sleeve, so that current-carrying parts of the electric heating element are electrically insulated from the sleeve and the position of the electric heating element is fixed in the sleeve, and
• at least partially compacting the sleeve, the electrical heating element arranged in sections of the sleeve which are to be compacted, and the filling material arranged in sections of the sleeve which are to be compacted

on. It is essential to the invention that, prior to the completion of the at least partial compression of the sleeve, a tube section is arranged at sections to be compacted, which consists of a second material having a second strength that is higher than the first strength.

In this way, the compression of the electric heater can be achieved very precisely and with process-reliable, highly reproducible results.

This is especially true for electric heaters with differently densified areas, because the area in which a given compaction is achieved can thus be locally defined and a controlled grading of different degrees of compaction can be effected. In addition, the additional pipe section made of a material with higher strength guarantees the ring clamping force during compaction.

It should be pointed out explicitly at this point that the step of at least partially compressing is of course also realized if the entire electric heating device is compressed at the same time.

The electric heating element may be, for example, a wound wire wound on a wound body, in particular a ceramic wound body, wound resistance wire, a self-supporting resistance wire or an embedded and positioned heating wire coil.

The filler is usually an electrically insulating material with the highest possible thermal conductivity. In particular, it may be magnesium oxide granules.

The arrangement of this filling material in the sleeve can therefore in particular mean the filling of an insulating powder, insulating granules or other insulating parts.

According to a particularly preferred embodiment of the method, the material constituting the sleeve is copper, aluminum, titanium or brass so as to provide a sleeve of copper, aluminum, titanium or brass. All these materials have in common that they have a relatively good thermal conductivity, but not very high strength.

The sleeve, which is preferably designed as a tube closed on one side, is preferably provided by being machined from the solid, deep-drawn from a sheet or step-pressed.

The preferred material for the sections of pipe to be compacted sections of pipe is a steel, in particular a stainless steel, so a high-strength material.

In a preferred embodiment of the invention it is provided that the arranging of the pipe sections in the sections to be compacted for at least one pipe section takes place in that it is pushed onto the sleeve so that it surrounds the section to be compacted in the radial direction. This not only brings a particularly simple precise positioning with it, but also allows a high-precision local force during compression, in particular by using a compacting tool, which initiates at least at the beginning of the compression process mainly on the suspended pipe section force.

According to a preferred development of this embodiment of the method, it is provided that the compression is carried out in such a way that, after the compression, the pushed-on pipe section is aligned with sections of the sleeve to which no pipe section has been pushed.

But it is also possible that the pipe section is inserted into the sleeve. This is particularly useful if the strength of the sleeve is too low to achieve the necessary ring clamping force or if a homogeneous surface of the electric heater is needed.

It is particularly preferred if the possibility of creating precisely defined non-compacted or weakly compressed regions is exploited to arrange at least one electronic component, in particular a sensor, a fuse and / or a switch, in the sleeve. This is preferably done by the electronic component is arranged together with the electric heating element in the sleeve, ie in particular as a preconfigured assembly.

The fact that a pipe section is arranged on the sleeve so that it projects beyond the sleeve, so in particular protrudes beyond an end face of the sleeve, in particular the possibility is created to provide the electric heater with a connection area with defined properties. For example, such an undesirable heat flow in the direction of the terminals of the electric heater can be largely avoided. In particular, it is possible for a further tube, which extends the sleeve concentrically, to be arranged in the region of the tube section projecting beyond the tube.

It may be advantageous to rework the bottom of the sleeve after compaction, in particular to rework so that a flat end surface is formed, which can be done for example by machining the soil. At the same time, however, it should be pointed out that deformation of the end face during compaction can be avoided by the method according to the invention with an adapted choice of the degrees of compaction of the respective regions in many cases, so that such a post-processing step becomes obsolete.

• 1a: die bereitgestellten Komponenten einer ersten Variante einer elektrischen Heizvorrichtung,
• 1b: eine Schnittdarstellung der zusammengesetzten Komponenten aus 1a vor dem Verdichten,
• 1c: eine Schnittdarstellung der aus den Komponenten aus 1a hergestellte elektrische Heizvorrichtung nach dem Verdichten,
• 2: eine zweite Variante einer mit dem Verfahren herstellbaren elektrischen Heizvorrichtung nach dem Verdichten,
• 3: eine dritte Variante einer mit dem Verfahren herstellbaren elektrischen Heizvorrichtung nach dem Verdichten,
• 4a: eine fünfte Variante einer mit dem Verfahren herstellbaren elektrischen Heizvorrichtung vor dem Verdichten,
• 4b: die Heizvorrichtung aus 4a nach dem Verdichten,
• 5a: eine fünfte Variante einer mit dem Verfahren herstellbaren elektrischen Heizvorrichtung vor dem Verdichten,
• 5b: die Heizvorrichtung aus 5a nach dem Verdichten,
• 6: eine sechste Variante einer mit dem Verfahren herstellbaren elektrischen Heizvorrichtung nach dem Verdichten,
• 7a: eine siebte Variante einer mit dem Verfahren herstellbaren elektrischen Heizvorrichtung vor dem Verdichten, und
• 7b: die Heizvorrichtung aus 8a nach dem Verdichten.

The invention will be explained in more detail with reference to figures that illustrate embodiments. It shows:

• 1a : the provided components of a first variant of an electric heating device,
• 1b : A sectional view of the composite components 1a before compacting,
• 1c : a sectional view of the components 1a manufactured electric heating device after compacting,
• 2 a second variant of a process-producible electric heating device after compaction,
• 3 a third variant of a process-producible electric heating device after compaction,
• 4a a fifth variant of a process-producible electric heating device before compacting,
• 4b : the heater off 4a after compacting,
• 5a a fifth variant of a process-producible electric heating device before compacting,
• 5b : the heater off 5a after compacting,
• 6 A sixth variant of a process-producible electric heating device after compression,
• 7a a seventh variant of an electric heating device producible by the method before compacting, and
• 7b : the heater off 8a after compacting.

Insofar as arrows are drawn in some figures which still show uncomplicated electrical heating devices, these in each case indicate in which direction the compression of the system takes place.

1a shows the partially preconfigured components of an electric heater provided for carrying out the further method steps 100 , One recognizes in particular that here as with a resistance wire 111 wrapped bobbin 112 trained electric heating element 110 , as well as the sleeve 130 made of copper and the pipe section 140 made of stainless steel. Naturally, both copper and stainless steel have strength, and the strength of stainless steel is higher than that of copper.

Also the electric heating element 110 is preconfigured insofar as an electronic component 150 , namely here a temperature sensor, end is arranged on the winding body and already a connection to connecting wires 160 was produced.

In the illustration of the electric heater 100 before the step of at least partially compressing in 1b is the electric heating element 110 in the sleeve 130 been arranged and the filler 120 in the form of magnesium oxide powder also in the sleeve 130 arranged so that current-carrying parts, namely the resistance wire 111 , the electric heating element 110 from the sleeve 130 are electrically isolated and the location of the electric heating element 110 in the sleeve 130 is fixed.

By the method step of at least partially compressing the electric heating device 100 this arrangement will then be in the in 1c converted form shown. In particular, here only a compression in the area of the pipe section 140 Made of stainless steel, making this a compacted section 101 and an uncompressed section 102 in which the electronic component 150 is arranged. The compression was carried out so that the pipe section 140 now in alignment with the course of the sleeve 130 in the uncompressed section 102 the electric heater 100 , runs.

2 shows a second variant of an electric heater which can be produced by the method 200 with condensed section 201 , uncompressed sections 202 . 203 , electric heating element 210 with resistance wire 211 and wound bobbin 212 , Filling material 220 , Sleeve 230 , Pipe section 240 , electronic component 250 and connecting wires 260 after the at least partial compression.

The difference to the electric heater 100 consists in the fact that the pipe section 240 the terminal-side end portion of the electric heater 200 and the sleeve 230 does not include, leaving a second non-compressed area 203 arises. This can be, for example, for some types of electrical connections between connecting wires 260 and electric heating element 210 and / or electronic component 250 make sense.

3 shows a third variant of an electric heater which can be produced by the method 300 with condensed section 301 , uncompressed sections 302 . 303 , electric heating element 310 with resistance wire 311 and wound bobbin 312 , Filling material 320 , Sleeve 330 , Pipe section 340 , electronic component 350 and connecting wires 360 after the at least partial compression.

Unlike the electric heater 200 protrudes at the electric heater 300 the pipe section 340 over the connection-side end region of the sleeve 330 In addition, in which the sleeve 330 outstanding area of the pipe section 340 an additional pipe 370 , in this embodiment again a stainless steel tube, which is the sleeve 330 extended concentrically. In this way, the heat transfer to the connection side can be reduced.

4a and 4b show a fourth variant of an electric heater which can be produced by the method 400 with condensed section 401 , uncompressed section 402 , electric heating element 410 with resistance wire 411 and wound bobbin 412 , Filling material 420 , Sleeve 430 , Pipe section 440 , electronic component 450 and connecting wires 460 before or after the at least partial compression.

The difference to the electric heater 100 consists in the fact that the pipe section 440 Part of a sleeve 430 surrounding further sleeve 441 is, both sleeves 430 . 441 in each case in the region to be compressed before compression have a larger cross-section than in the non-compacting area.

5a and 5b show a fifth variant of an electric heater which can be produced by the method 500 with condensed section 501 , uncompressed section 502 , electric heating element 510 with resistance wire 511 and wound bobbin 512 , Filling material 520 , Sleeve 530 , Pipe section 540 and connecting wires 560 before or after the at least partial compression.

The electric heater 500 in this respect has a relationship to the electric heater 300 on, as with this the pipe section 540 the sleeve 530 surmounted in the direction of the connection. Unlike the electric heater 300 is in the embodiment according to the 5a and 5b however, no further pipe is arranged in this area. Another difference to the electric heater 300 consists in that the sleeve 530 a reinforced floor 531 having significantly increased wall thickness. This is particularly useful if any deformation of this soil during compaction by particular machining post-processing, for example by twisting, should be compensated. In addition, no electronic component is present.

6 shows a sixth variant of an electric heater which can be produced by the method 600 with condensed section 601 , electric heating element 610 with resistance wire 611 and wound bobbin 612 , Filling material 620 , Sleeve 630 , Pipe section 640 and connecting wires 660 after compacting.

The electric heater 600 is structurally similar to the electric heater 500 constructed, unlike this, however, is a thermocouple on the bottom side 650 available and the pipe section 640 take the sleeve 630 completely on.

7a and 7b show a seventh variant of an electric heater which can be produced by the method 700 with condensed section 701 , uncompressed section 702 , electric heating element 710 with resistance wire 711 and wound bobbin 712 , Filling material 720 , Sleeve 730 , Pipe section 740 , electronic component 750 and connecting wires 760 before or after the at least partial compression.

The difference to the electric heater 100 according to 1a to 1c consists in the fact that the pipe section 740 in the sleeve 730 pushed in and not pushed onto it.

LIST OF REFERENCE NUMBERS

100,200,300,400,500, 600,700

Electric heater

101,201,301,401,501, 601,701

compacted section

102,202,302,303,402, 403,502,602

non-sealed section

110,210,310,410,510, 610,710

electric heating element

111,211,311,411,511, 611,711

resistance wire

112,212,312, 412,512, 612,712

bobbin

120,220,320,420,520, 620,720

filling material

130,230,330,430,530, 630,730

shell

140,240,340,440,540, 640,740

pipe section

150,250,350,450,550, 750

electronic component

370

pipe

441

shell

531

ground

650

thermocouple

Claims (10)

A method of making an electric heater (100,200,300,400,500,600,700) comprising the steps of providing a sleeve (130,230,330,430,530,630,730) of a first material having a first strength, disposing an electrical heating element (110,210,310, 410,510,610,710) in the sleeve (130,230,330,430,530,630,730), arranging a fill material (120,220,320,420,520,620, 720) in the sleeve (130,230,330,430,530,630,730) so that current carrying parts of the electrical heating element (110,210,310,410,510,610,710) are electrically isolated from the sleeve (130,230,330, 430,530,630,730) and the location of the electrical heating element (110,210,310, 410,510,610,710) in the sleeve ( 130,230,330,430,530, 630,730), and - at least partially compacting the sleeve (130,230,330,430,530,630,730), the electrical heating element (110,210,310,410, 510,610,710) disposed in sections of the sleeve (130,230,330,430,530,630,730) being compacted, and d in sections of the sleeve (130,230,330,430,530,630,730), which are to be compacted arranged filling material (110,210,310,410,510,610,710), characterized in that prior to completing the at least partially compressing the sleeve (130,230,330,430, 530, 630, 730) at sections to be compacted a pipe section (140,240,340,440,540, 640,740) is arranged, which consists of a second material having a second strength which is higher than the first strength. Method according to Claim 1 , characterized in that a sleeve (130,230,330,430,530,630,730) made of copper, aluminum, titanium or brass is provided. Method according to Claim 1 or 2 , characterized in that a pipe section (140,240,340,440,540,640,740) made of steel, in particular stainless steel is arranged at sections to be compacted. Method according to one of the preceding claims, characterized in that the pipe section (140,240,340,440,540,640,740) is pushed onto the sleeve (130,230,330,430, 530, 630, 730). Method according to Claim 4 , characterized in that the compression is carried out so that after the compression of the deferred pipe section (140,240,340,440,540,640) with portions of the sleeve (130,230,330,430,530,630) on which no pipe section (140,240,340,440,540,640) is pushed aligned. Method according to one of Claims 1 to 3 , characterized in that the pipe section (740) is inserted into the sleeve (730). Method according to one of the preceding claims, characterized in that at least one electronic component (150,250,350, 450,550), in particular a sensor, a fuse and / or a switch, in the sleeve (130,230,330,430,530,630,730) is arranged. Method according to Claim 7 , characterized in that the electronic component (150, 250, 350, 450, 505) is placed in the sleeve (130, 230, 3030, 3030, 3030, 3030) together with the electrical heating element (110, 210, 310, 410, 1010, 610, 710). Method according to one of the preceding claims, characterized in that a pipe section (340,440,540) on the sleeve (330,430,530) is arranged so that it projects beyond the sleeve (330,430,530). Method according to Claim 9 , characterized in that in the sleeve (330) projecting portion of the tube section (340) an additional tube (370) is arranged, which extends the sleeve (340) concentrically.

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